Directions:In each of the following groups of words,there are four underlined letters or let-ter combinations marked A,B,C and D.Compare the underlined parts and iden-tdtify the one that is different from the others in pronunciation.Mark your answer by blackening the corresponding letter on the Answer Sheet.

• A、pension

• B、mission
• C、tension
• D、revision

(57)___

(31)___

• A、How

• B、Whether

• C、Before

• D、As